A synthesis of (-)-tashiromine and formal synthesis of (+)-tashiromine utilizing a highly enantioselective pyrrole/cobaloxime π-cation cyclization

Tetrahedron Letters

Volumn 38, Issue 40, 1997, Pages 7007-7010

  Gage, Jennifer L ^a   Branchaud, Bruce P ^a  

^a UNIVERSITY OF OREGON   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

INDOLIZIDINE ALKALOID; TASHIROMINE; UNCLASSIFIED DRUG;

ARTICLE; CHIRALITY; DRUG SYNTHESIS; GAS CHROMATOGRAPHY; HIGH PERFORMANCE LIQUID CHROMATOGRAPHY; IN VITRO STUDY; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; REACTION ANALYSIS; STEREOCHEMISTRY;

EID: 0030875301     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(97)01638-9     Document Type: Article

References (31)

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29. Compound (S)-23 from a previous synthesis was determined to be 97.7% enantiomerically pure (95.4% ee) [(S)-pentanetriol produced from L-glutamic acid by the methodology shown has variable optical purity]. The amount of (R)-23 present in the sample from the more recent synthesis was below the detection limit of the chiral HPLC system.
30. (a) HPLC analysis was performed on a Chiralcel OD-H analytical column (0.46 × 25 cm) and monitored at 254 nm. (b) GC analysis on a column containing a chiral stationary phase was performed on a β-Dex 110 capillary column: 30 m × 0.25 mm ID × 0.25 μm film thickness.
31. 19F NMR measurements used in this study, the reaction of (-)-21 with (±)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride provides authentic NMR standards of both the major and the minor diastereomers produced in the reaction of (-)-21 with (+)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride.